At 9-years-old, Dunham wrote a vow of celibacy, promising herself she'd remain a virgin until she graduated from high school. "This seemed important because I knew my mother had waited until the summer after she graduated and also ["My So-Called Life" character] Angela Chase seemed pretty messed up by her experience at that flophouse where high school kids went to copulate," she explained.

It was a vow she ended up keeping; she lost her virginity during her sophomore year of college at Oberlin. "I met Jonah* in the cafeteria. He was roommates with an emo kid who worked at the video store and had a crush on my best friend, Audrey," she wrote.

Dunham set her sights on Jonah and "casually" invited him to a party she was throwing. He stayed long after the rest of the guests had left and the two talked, first animatedly, and then in the nervous generalizations that substitute for kissing when everyone is too shy."

Dumham writes that she then told him that her dad, artist Carroll Dunham, paints "huge pictures of penises" for a living. Since there's nothing sexier than talking about the penis paintings your dad made, her suitor naturally asked if he could see them online.

"I grabbed him by the scruff of the neck and just went for it," she recalled. "I removed my shirt almost immediately, and he seemed fairly impressed. Wearing just a too-tight slip-skirt from the local Goodwill, I hopped up to get the condom from the “freshman survival pack” we had been given (even though I was a sophomore)."

Dunham's first time was awkwardly interrupted by her best friend Audrey, who burst into her dorm room without knocking. "There she found Jonah on top of me doing what grownups do. She understood the magnitude of the occasion and through her tears shouted, “Mazel tov!" Dunham wrote.

They only had sex once, she says, but she's already translated the experience to film. "Later, I wrote that virginity-loss scene almost word for word in my first feature film, "Creative Nonfiction," minus the part where Audrey busted the door down. When I performed that sex scene, my first, I felt more changed than I had by the actual experience of having sex with Jonah. Like, that was just sex, but this was my work," she explained.

With experiences like this, it's no surprise the sex scenes in "Girls" don't feature your average steamy Hollywood lovefest.

"I often said that I've felt a little unfairly duped by the sex I see on television," Dunham told "CBS This Morning." "I'm not saying this is every girl's sexual experience, but I am saying that sex isn't always glamorous, painful, it's embarrassing, it's complicated and I really wanted to see scenes where girls weren't wearing negligees and sighing."